I had put a code in the activity_main.xml that was in another color, when I clicked the light to see what information it showed, I created another xml with the name activity_main.xml (v21 ) .
Remove this second xml that was created, and the first activity_main.xml also disappeared, so I re-created the activity_main.xml and put the code I had.
But when I'm going to try the application, it shows me this error message
I do not know if with this capture of the error it can be useful to see where the problem is, the Logcat I do not know what text to copy to put it here, because there is a lot.